A new tool released by Google to speed up web surfing has been hit by privacy concerns. It emerged that users visiting sites where they can log in - including Neowin - are being logged in as other users of the service.

Google Web Accelerator is currently in beta and automatically stores and updates the content of pages accessed through it. However, ZDNet reports at least one user having problems as he suddenly discovered he was logged in as someone else - a problem replicated here.

"I went to the Futuremark forums and noticed that I'm logged in as someone I don't know," the user said on a Google discussion group. "I've used Google's Web Accelerator for a couple of hours, visited lots of sites where I'm logged in. Now I wonder how many people used my cache. I understand it's a beta, sure, but something like that is totally unacceptable."

No comment yet from the search engine giant on the issue. However, it did warn that information sent through cookies would be "temporarily cached" - it's not clear yet if that is where the problem lies.